Exercise 3 Page p25

The perimeter of a figure is found by adding the lengths of all of the sides. In the given diagram, the hash marks indicate that the opposite sides of this shape have equal lengths.

This means that our figure is a parallelogram. Because a parallelogram has two sets of sides with equal lengths, known as $a$ and $b,$ we can add one of each of these and then multiply the sum by $2$ to find the perimeter. We can substitute $a=27$ and $b=18$ into the formula and simplify to find the perimeter. The perimeter is $90$ inches.